1. Field of the Invention
This invention relates to a compact circuit to selectively drive any one of a plurality of transistor devices which control the operation of a display, such as a light emittting diode display found in a handheld calculator, or the like.
2. Prior Art
A conventional readout display, such as a light emitting diode display found in hand-held calculators, or the like, in frequently powered by a 9 volt battery. However, the available energy which can be supplied from the battery typically diminishes (i.e. to 6 volts) with the continued passage of time and battery use. As a result, the display is undesirably dimmed.
It is customary, in the prior art, to include an additional external power supply to insure that suitable power is available to adequately energize the display. This results in the undesirable effects of increased calculator cost and size.